From the tons sold in legal medical-marijuana dispensaries to the tons imported each year from Mexico, Arizona knows its cannabis. Here's a roundup of last week's biggest pot news stories that affect the Grand Canyon State...

Arizona Legalization Campaign Submits Signatures to State Welcome to the Fourth of July edition of Arizona's Week in Weed — an appropriate day to think about marijuana freedom. In this brash, last-of-the-Lower-48, gun-shop-on-every-corner state, it appears certain that voters will weigh in on a transformative cannabis-legalization measure this fall.

This past Thursday, the Campaign to Regulate Marijuana Like Alcohol in Arizona (CRMLA) submitted 258,582 petition signatures, far exceeding the 150,642 required to qualify for a spot on November's ballot.

The CRMLA proposes a gradual approach, allowing for future expansion of storefront cannabis sales, rather than ram it down Arizonans' throats by the kilo right away. While Colorado has about 900 retail stores, legalization in Arizona would begin with about 150. Individual cities could hold referenda to limit the number of shops to the number of existing medical-marijuana stores. With that in mind, medical-marijuana companies and shrewd speculators have been acquiring the property and licensing necessary to survive in what would be a new recreational industry.

Might right-leaning, establishment-weary Arizona voters be amenable to a Cannexit from decades of War on Drugs policies? If so, that could tip the balance in a close election by adding to the left-leaning bloc that's already inclined to say "yes."

Also last week, Arizona's Joint Legislative Budget Committee released its estimate of the potential sales-tax revenue from the initiative. In part, the committee based its calculations on the premise that there are 587,100 adult marijuana users in Arizona. Subtracting the roughly 100,000 medical-marijuana patients for whom possession is already legal, that leaves nearly a half-million grownups who are committing felonies under current law.

Catholic Church, Cathy Herrod, and State GOP Come Out Against Arizona Cannabis Freedom Our state's enemies of what the Founding Fathers called "hemp" aren't all low-rent radio personalities, prosecutors, misguided potheads, and corporate weenies. Now it's getting serious: As of last week, the ranks of on-the-record foes of the CRMLA include local leaders of the Roman Catholic Church, the state Republican Party, and anti-abortion activist Cathy Herrod.

"Legalizing the recreational use of marijuana sends a message to children and young people that drug use is socially and morally acceptable," declared Bishops Thomas Olmsted (Phoenix) and Gerald Kicanas (Tucson), along with a few other Catholic higher-ups, in a written statement. "As people of faith, we must speak out against this effort and the damaging effects its passage would have on the children and families of Arizona."

Catholic voters don't always align with the strict values of religious leadership, though — think of the issues of the death penalty and abortion.

For years now, Republican politicians in Arizona including Maricopa County Attorney Bill Montgomery and Yavapai County Attorney Sheila Polk have fought against efforts to eliminate felony prohibition. Donors to Polk's group, Arizonans for Responsibly Throwing Your Ass in Jail, include chambers of commerce, the wife of a state supreme court justice, the state's largest power utility, and the alcohol industry. Cathy Herrod of the Center for Arizona Policy joined the clique last week with her own fact-challenged statement.

"Pot shops will pop up all over town," reads one sample from the June 30 statement. "Within two years after legalizing marijuana in Colorado, pot shops now outnumber Starbucks, liquor stores, and public schools."

Herrod's incorrect. The CRMLA calls for an initial 150 or so retail outlets statewide, more than 90 of which already sell medical marijuana under the state's 2010 law. Any major future expansion would have to be sanctioned by Arizona municipalities.

Robert Graham of the Arizona Republican Party also issued a statement last week urging Arizonans to reject the CRMLA.

Last month, we told you how recent studies showed that 20-year marijuana users seemed to be at risk only for a greater rate of gum disease, and how the most detailed analysis yet of Colorado teens showed no rise in cannabis use since total legalization — the opposite of what prohibitions claim.

Making the rounds in the news media last week: a fascinating new study that supports the idea of marijuana being good — if not the cure — for the memory-robbing Alzheimer's disease.

Specifically, it's the well-known psychoactive compound THC that helps. Scientists from the Salk Institute in La Jolla, California, found that THC and other compounds in cannabis scrub a toxic protein called amyloid beta from cells.

"Although other studies have offered evidence that cannabinoids might be neuroprotective against the symptoms of Alzheimer's, we believe our study is the first to demonstrate that cannabinoids affect both inflammation and amyloid beta accumulation in nerve cells," said Professor David Schubert, the senior author of the paper.